1. Field of the Invention
The invention relates in general to a disk structure and a manufacturing method thereof and an optical tweezers device using the same, and more particularly to a disk structure having a reflective layer, a manufacturing method thereof and an optical tweezers device using the same.
2. Description of the Related Art
The application of the optical controlling technology includes optical levitation and laser cooling and trapping, etc. With the development of the optical controlling technology, an optical tweezers device has been widely used in many fields, such as micro-electro mechanical field, biological field or medicine field; furthermore, the optical tweezers device with a single laser beam presented by Arthur Ashkin et al. is applied frequently in this field. The laser beam is focused within an optical tweezers device by a lens with high numerical aperture (NA) ratio and high magnification to control a nano-level particle at the focal point. As the optical tweezers device controls the particle neither touching nor invading it, the structure of the particle would not be damaged. Therefore, the optical tweezers device can be effectively used in controlling biological particles, such as cells, blood cells, sperms, or microbes.
Presently, laser beam applications of optical tweezers can be categorized into single laser beam and dual laser beam. In general, when applying the single laser beam to the optical tweezers device, the single laser beam has to pass through a lens with higher NA ratio so as to get a larger force for controlling a particle. However, a lens with high NA ratio is expensive. Mention of the dual laser beam, although it doesn't need to be with a high NA ratio lens, two single laser beams are still required to form the dual laser beam. Therefore, the usage cost of the dual laser beam is comparably high as well.